One technique used in the design and manufacture of certain types of battery cells, such as rechargeable lithium-ion (“Li-ion”) cells, is the so-called “jelly roll” technique. This technique involves winding two thin, flat metal sheets that form the anode and cathode electrodes of the battery cell, respectively, around a spindle or mandrel, with a thin, flat insulative layer between them, to form an electrode roll. A conductive terminal is bonded (e.g., welded) to each electrode to provide an external terminal of the battery cell. The electrode roll is often pressed into a flatter shape before enclosing it in a casing.
For some applications, it is desirable to have a battery cell that is curved or bent in a specified direction, to meet space constraints and/or to make the battery cell better conform to the form factor of the end product in which it will be used. In such cases the electrode roll or the entire assembled cell is pressed around a cylindrical tool to form it into a curved shape. In some applications, it is desirable to have a thicker battery cell, to provide certain desired electrical performance characteristics. However, a requirement for a curved battery cell may impose limits on how thick the electrode roll (and hence the cell) can be made, due to limitations of existing manufacturing equipment and/or the materials of the electrodes.